JPH11327096A - Uniformly mixed dry photographic processing composition using hot melt binder and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a uniformly mixed dry photographic processing composition low in cost, easy and safe in use and capable of easily producing by aggregating a uniformly dried mixture while simultaneously applying a hot melt binder polymer under a condition, in which aggregate having desired size is formed. SOLUTION: The uniformly dried mixture is formed by mixing >=2 kinds of dry photographic processing chemical components sufficiently to give the desired uniformity. And the aggregate having the desired sized and desired uniformity is formed by aggregating the uniformly dried mixture while simultaneously applying the hot melt binder polymer (where, the quantity of the hot melt binder polymer in the uniformly mixed photographic processing powdery composition is <3 wt.%) under the condition, in which the aggregate having the desired size is formed. The resultant aggregate has >100 μm average diameter. Then the quantity of the particle or the aggregate having <20 μm diameter is <=0.2 wt.% of the powdery composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a composition for uniformly mixed and dried photographic processing and a method for producing the same. More particularly, the present invention relates to black and white or color photographic processing compositions in the form of a powder, wherein two or more dry photographic processing chemicals are homogeneously mixed therein.

[0002]

BACKGROUND OF THE INVENTION Conventional images are prepared by combining a silver halide photographic material imagewise exposed to form an image with one or more of the various photochemical components necessary to form black and white and / or color images. It can be obtained by further processing with a photographic processing solution. In any case, such materials provide a developer (to "develop" the silver image from the exposed silver halide grains) and a fixer (to "fix" and remove unexposed silver halide). In order to stabilize the image, a photochemical treatment is required.
Color photographic processing requires additional steps to form an acceptable dye image, for example, a silver bleaching step between color development and fixing.

[0003] Various chemical formulations used in conventional photographic processing processes have been manufactured in both liquid and solid forms. Many of the required photochemical components are already in solid form, and in early photographs, solid processing compositions were common. However, it is often difficult to uniformly mix the solid components, and therefore, it has often been necessary to mix for a long time to prepare an aqueous solution having a usable strength. In addition, some of the photochemical components are reactive with each other, and if mixed, a significant decrease in activity cannot be avoided, and a decrease in shelf life or stability was apparent.

[0004] Most recently, commercial compositions have been produced, transported, and used as aqueous solutions. They may be supplied in a concentrated form to minimize costs associated with weight and volume, but require dilution at the time of use.

[0005] Concentrates can be stored only for a limited period of time, even though they are somewhat economically advantageous, and the cost of transport and the cost of solvent are still reduced even though the concentrates are reduced. Storage costs increase. Accordingly, the photographic industry has long sought a method of providing a dry, stable photographic processing formulation. In recent years, in response to these needs, many manufacturers have developed powders, granules, solid tablets and other dry forms.

To date, solid compositions have not been widely accepted in the art. One reason for this is that the fine powder composition poses a health hazard to workers who are trying to formulate a working solution when the fine dust is dusted in the workplace. In addition, powder chemicals are difficult to mix uniformly on a small scale, for example, in relatively small laboratories. To obtain high uniformity,
High energy mixing is required and many developers cannot afford the necessary mixing equipment or space. As the powder becomes finer, the problem of dust increases and solubilization becomes more difficult.

In response to these problems, there are various means in the art for producing powdered or particulate photochemicals, such as fluidized bed agglomerators (see US Pat. No. 4,923,786), extrusion methods (US Pat. No. 3,981,732)
And lyophilization (see U.S. Pat. No. 4,816,384)
Has been used.

[0008] Solid tablet chemicals have also evolved in the art (see, eg, US Pat. No. 5,316,898) but have not been widely accepted because they are more expensive than conventional photochemical compositions. .

[0009]

SUMMARY OF THE INVENTION A homogeneously mixed dry photographic processing composition which is inexpensive, easy to use and safe, and can be easily manufactured using readily available equipment and easy to implement methods. It is clear that there is a need in the industry for things. The present invention aims to solve these problems and to meet these needs.

[0010]

SUMMARY OF THE INVENTION The present invention is a homogeneous mixed photographic processing powder composition comprising two or more photographic processing chemical components, wherein agglomerates having a diameter of less than 20 μm are included in the composition. The composition provides less than 0.2% by weight and less than 1% by weight solvent and less than 3% by weight hot melt binder polymer in the composition.

The composition comprises: A) two or more dry photographic processing chemical components:
The target uniformity (where the target uniformity is defined as two or more random samples of the same size in the uniform dry mixture being ± 4% of the target weight% of each component of the photographic processing chemical component)
) To form a homogenous dry mixture thereof, and B) under conditions that form a target size agglomerate, the hot melt binder polymer (provided that The amount of hot melt binder polymer in the resulting homogeneous mixed photographic processing powder composition is 3
(By weight) is simultaneously applied to form an agglomerate having a target size and uniformity by agglomerating the homogeneous dry mixture. it can.

[0012]

DETAILED DESCRIPTION OF THE INVENTION The present invention is readily practiced using commercially available equipment to provide a very uniform photographic processing composition comprising photochemicals in a uniform size and uniformly mixed agglomerate. Can be manufactured. The resulting agglomerates are large enough to avoid the problem of dust, but small enough to be easily dissolved when making the working solution. The powder composition may include all or some of the components required for a given processing bath. Thus, the composition can be a single part (partially composed) photographic processing kit or a component of a multi-part (multiple part) photographic processing kit.

The agglomerates in the compositions of the present invention are easy to dry, store and meter into aqueous solutions, are relatively inexpensive, are readily soluble in water, and are stable during transport and storage. It is.

These advantages are achieved by a unique combination of the manufacturing process and the conditions described herein. The apparatus itself used in the method of the present invention is not new, but has not previously been used to form a photographic processing composition having the essential properties described above. Specifically, when the dry photographic processing chemical components are mixed in a manner that uses the apparatus to meet the "target" uniformity required for a given composition, the sample in the composition will have a composition and The proportions of the chemical components are substantially the same. That is, in a random sample of a composition, the deviation in composition is no more than ± 4% of the predetermined or “target” weight percent of the components required for the composition.

By "target weight%" is meant that, for a given photographic processing composition, the target or target formulation contains a predetermined target or target amount (eg,% by weight) of each photographic processing chemical component. . Therefore, each photographic chemical component should be present in the composition at a predetermined target weight percent, and the present invention provides a formulation wherein the components are present in an amount within ± 4% of the target weight percent of each component. provide.

When a homogeneous mixture is obtained, the particles are agglomerated at the same time that the hot melt binder polymer is applied, resulting in a target size agglomerate without losing the target uniformity obtained during the mixing process. Can be Various details regarding the implementation of these steps are provided below, along with representative conditions, equipment and operation.

The use of a hot melt binder in the agglomeration process has several advantages. The need to dry the composition after flocculation is less than when using an aqueous binder mixture. Also, when an aqueous binder mixture is used, it is relatively likely that some of the photographic processing chemical components will be oxidized, but the use of a hot melt binder reduces this problem. Thus, the need to apply a separate antioxidant during flocculation is relatively low, and the present invention is more advantageous for producing compositions that are inherently relatively unstable in the presence of water or air.

The homogeneous mixed photographic processing powder composition of the present invention comprises at least two dry photographic processing chemical components,
For more complex photographic processing steps (eg, color development), up to 15 such components can be included. All of these chemical components are uniformly mixed. This means that for a given composition, the "target uniformity" is met during the mixing process (see below).

As used herein, the terms "photochemicals" and "chemical components for photographic processing"
To form the desired image in the exposed photographic element,
Used interchangeably to mean chemicals or compounds that directly or indirectly affect the performance of a particular photographic process.

The photographic processing chemicals are generally provided in a suitable dry form, powder or granule, when mixed.
They can be supplied as single parts (partial components) or as multiparts (multiple components). Usually, multiple parts "components" of a mixture are used when some of the chemical components are not readily compatible with one another.

"Target uniformity" means that when two or more identically sized random samples of a dry mixture are analyzed, the target weight percent of each of the various photographic processing chemicals contained in the sample is substantially equal. Is the same as
It means within ± 4% by weight, preferably ± 2% by weight, more preferably ± 1% by weight of the target weight%. "Target weight%" depends on the activity and properties required for a given composition. For example, the target weight percent of each component of the developer composition will likely be different from the target weight percent of each component included in the fixing composition. If you are skilled in the art,
One can readily ascertain what target weight percent is appropriate for a component of a composition. Thus, uniformity of chemical composition and efficacy is guaranteed throughout the composition.

Such high uniformity is achieved by vigorous mixing of the photographic processing chemical components (or the various components of the formulation) in the appropriate parts of the equipment. One suitable means of such intense mixing is the Patterson Company and Patterso, known as "V-blenders".
Some are commercially available from sources such as the n-Kelly Company. The "V-blender" can also include internal baffles or "pressure intensifiers" or "bars" that enhance mixing, i.e., provide more shear for the mixing operation. Uniform mixing may also be possible using a double cone blender with intensifier bars.

The key to this mixing is to provide a sufficiently high shear for a time sufficient to achieve said uniformity.
Uniformity can be assessed during the mixing operation, if necessary, by taking random samples of the same size and analyzing them for the weight ratio of the various photographic processing chemicals. The skilled photochemist will be able to determine the desired weight percent of the components based on their activity and use in photographic processing. If the random sample is within the required deviation (eg, ± 4% by weight of the target weight%), it can be said that uniform mixing has been performed. If the two samples are outside the required deviation, additional mixing time will be required. After routine experimentation, appropriate mixing times and conditions can be readily determined and used in subsequent mixing operations. Suitable mixing times also vary depending on the equipment used, but can be from 10 minutes to several hours.

Another advantage of such strong mixing is a uniform particle size distribution. Preferably, the powder particles obtained by mixing have an average diameter of 40-80 μm. This uniform particle size distribution contributes to the uniformity of the agglomerates obtained after mixing.

The specific apparatus and operation for mixing will be described in the following examples. After such intense mixing, the powder particles agglomerate into larger particles having a uniform size and composition. These agglomerates generally have an average diameter of 2
It is larger than 0 μm, preferably larger than 100 μm.
Thus, particles or agglomerates with a size of less than 20 μm
Not more than 0.2% by weight of the powder composition.

For the upper limit of the particle size range, the size of the agglomerates is generally less than 1000 μm, preferably 900 μm.
Is less than. A preferred range for the target size of the agglomerates is 125-850 μm for at least 95% of the agglomerates
It is. Agglomerates having a particle size of 1000 μm or more account for less than 1% of the total dry composition weight.

Both agglomerates have the same homogeneity (ie, "target homogeneity") in the target weight ratio of photochemicals obtained in the intense mixing step. Agglomeration is performed by a number of suppliers (eg, Ferro-Tech Company and Teledyne).
-Read Co.) can be carried out using a conventional aggregating apparatus such as a disk pelletizer obtained from Co., Ltd. Alternatively, agglomeration can be performed using a "rolling plane" pelletizer as is commercially available from the same supplier. The conditions and operation for using such a device are readily understood from the instructions accompanying the device, and by modifying as described herein, the size and uniformity of the agglomerates. Desired results will be obtained. For specific operations and devices,
This is described in Example 1 below. For example, in a rolling plane pelletizer, adjustment of the pan rotation speed and angle can be used to control the size of the agglomerates.

Throughout the agglomeration, the dry mixture is contacted (eg, sprayed) with a hot melt binder polymer that, when cooled, effectively adheres the particles of the composition to one another to form agglomerates.

Useful hot melt binder polymers generally have a melting temperature higher than 40 ° C., preferably higher than 60 ° C., more preferably 80 ° C. or higher. Generally, the binder polymer can be any higher than 40 ° C., provided that the melting temperature is not high enough to adversely affect the photographic processing chemistry (eg, photochemical activity or other necessary functions) in the agglomerated dry mixture. It can have a melting temperature. In addition, useful polymers must be water-soluble or water-dispersible (when dissolved in working strength photographic processing solutions) or readily filterable and used in working strength solutions. In some cases, it must be inert to photographic processing components.

[0030] Blends of hot melt binder polymers can also be used. Representative examples of hot melt polymers are polyethylene glycol, polypropylene glycol, polyvinyl alcohol and polyvinyl pyrrolidone. Polyethylene glycol is preferred.

The hot melt binder polymer is generally applied to a dry mixture of particles as a spray of hot droplets.
Importantly, the resulting hot melt binder polymer in the dry composition of the invention is neither too low nor too high. If the binder polymer is too low, the agglomerates will probably be too small and "dust" of the composition will be a problem. If there is too much binder polymer, the size of the agglomerates will be too large and the uniformity of the photographic processing chemical will likely be reduced. Generally, the amount of hot melt binder polymer in the final dry composition will be at least 0.25% by weight, preferably at least 0.5% by weight and generally no more than 3% by weight and preferably 1% by weight based on total dry composition weight. Weight percent or less.

Unlike other flocculation operations, there is no need to apply a separate antioxidant (or preservative) to the homogeneous dry mixture to prevent oxidation of the chemical components in the composition. Also important for the stability of the composition is that the solvent contained in the dry composition of the present invention is less than 1% by weight based on the total composition weight,
Preferably, it is less than 0.5% by weight. For this reason, after the formation of agglomerates, a drying step using suitable drying equipment and conditions that do not adversely affect the photographic processing chemical components in the composition may be required. However, one advantage of hot melt binders is that the need for drying is significantly reduced due to the relatively low water added to the composition. In many cases, no drying is required.

An important feature of the drying composition of the present invention is that it is readily soluble in water and can be readily used in photographic processing with minimal mixing and stirring. Solubility can be measured by observing whether a 1 g sample of the composition dissolves in 100 g water at ambient temperature within 120 seconds while stirring with a 2.54 cm stir bar at 350 rpm. Fast dissolution is desirable. In some cases, the solubility can be increased by the presence of additional "components" of the multi-part processing kit.

The composition for dry photographic processing of the present invention can be a single composition required for a predetermined processing step,
It can also be a component of a multi-part photographic processing kit that contains two or more dry or liquid components that are mixed to perform a given processing step.

The composition may be a photographic developer composition (black and white or color), a bleaching composition, a bleach-fixing composition, a fixing composition, a dye image stabilizing composition, or a black-and-white or color negative or reversal film or print. Mention may be made of paper, motion picture films or prints, radiographic films, graphic arts films, or any other composition that can be used to form images in any other silver halide photographic imaging material.

The chemical components of such materials and the structure of the layers are known and are described, for example, in Research Disclosure, publicati
on 38957, 592-639 (September 1996) and many of the publications mentioned therein. Resear
ch Disclosure is a trademark of KennethMason Publications Ltd.,
Dudley House, 12 North Street, Emsworth, Hampshire
PO10 7DQ England publication.

For example, black and white developer compositions generally include one or more developing agents, including, but not limited to, dihydroxybenzene developing agents and ascorbic acid (and derivatives thereof). Such materials are known and are described, for example, in U.S. Patent Nos. 4,269,929 and 5,702,875. Hydroquinone is a preferred dihydroxybenzene developing agent and ascorbic acid is one of the preferred ascorbic acid type developing agents.

The developer composition generally further comprises one or more auxiliary developing agents (also known as auxiliary or additional developing agents), for example, US Pat. No. 5,264,32.
No. 3 including the preferred 3-pyrazolidone compounds (also known as "phenidone" type compounds).
Other common ingredients include antioxidants (eg, sulfites), buffers (eg, carbonates and borates), antifoggants, surfactants, antisludge agents, and metal ion chelators. Can be

[0039] Color developing compositions are also known. These are generally described in U.S. Pat. No. 4,892,804 and Research.
Disclosure, Section XIX, including one or more color developing agents (e.g., primary aromatic amino color developing agents including p-phenylenediamine). Such compositions generally further comprise one or more antioxidants (or preservatives), such as sulfites and hydroxylamines as described above, antifoggants, metal ion chelators (sequestrants). Also known as agents), surfactants, buffers, biocides or antifungals, anti-sludge agents, optical brighteners (or anti-stain agents), water-solubilizing agents,
Contains development accelerators and other ingredients known to those skilled in the art.

The bleaching solution, bleach-fixing solution and fixing solution are generally
Used after development of photographic materials. The components of such a solution are known. The bleaching and bleach-fixing solutions generally contain one or more bleaching and / or fixing agents.
Bleaching agents include peroxides, periodates, persulfates, metal salts (eg, ferric salts) and complexes of carboxylic acids. Fixing agents include thiosulfates, thiocyanates and other compounds that solubilize silver halide in photographic materials. Such solutions may also include silver rehalides, buffers, metal ion chelators, biocides,
Bleaching accelerators, fixing accelerators and other ingredients well known to those skilled in the art can be included.

Stabilizing solutions are also known and are described in the Resear
ch Disclosure. These include one or more surfactants, dye image stabilizing compounds, metal ion chelators, optical brighteners, stain inhibitors, antiscum agents, biocides, buffers and known to those skilled in the art. And other components.

For all of the compositions of the present invention, those skilled in the art will know the various amounts of photographic processing chemicals to be incorporated into a given composition for the desired photographic processing.
An important aspect of the present invention is that for a given composition, the mixing and agglomeration steps provide the desired uniformity of the photographic processing chemicals consistent with the desired "target weight ratio" between the chemicals. .

[0043]

The following examples are representative of some of the dry photographic processing compositions of this invention. Some of these are manufactured as "single-part" compositions and others are included as multi-part photoprocessing kits.

Example 1: Preparation of a black-and-white radiographic developer A two -part black-and-white developer usable for processing radiographic films was prepared as follows. Each "part" was manufactured as a dry powder. Each "part" can be packaged as a component of a processing kit. Each "part" contained the following chemical components:

Part A : ascorbic acid developing agent 6.11 kg 4-hydroxymethyl-4-methyl-1-phenyl-3-pyrazolidone 0.477 kg benzotriazole 0.038 kg potassium bromide (powder) 0.764 kg sodium sulfite 7. 6 kg diethylenetriaminepentaacetic acid pentasodium salt 0.328 kg Part B : Potassium carbonate buffer

A commercially available V- including a disintegrator (or intensifier)
In a blender (Patterson-Kelly Company), under ambient conditions, Part A was subjected to shell 16 rpm and a disintegrator 2300 rpm.
For 20 minutes. The resulting powder, mixed vigorously, was then placed in a commercially available Ferro-Tech rolling plain pelletizer and subjected to agglomeration operations for 30 minutes under ambient conditions. During the flocculation operation, polyethylene glycol 800
(800 mol. Wt.) As a hot melt was sprayed onto the uniformly dried mixture at a rate of 16 mg / min. Antioxidants were not applied to the homogeneous dry mixture.

Desired uniformity of chemical components for the obtained random sample of agglomerates (within ± 2% of target weight%)
Agglomerates or particles with a diameter of less than 20 μm are less than 0.2% by weight of the composition,
Agglomerates with a diameter greater than 1000 μm were less than 1% by weight. The amount of polyethylene glycol 800 contained in the obtained aggregate was less than 3% by weight based on the total weight of the composition.

Example 2: Preparation of a color developer A three-part color developer which can be used for processing a color negative film was prepared as follows. Each "part" was manufactured as a dry powder. Each "part" can be packaged as a component of a processing kit. Each "part" contained the following chemical components:

Part A : CD4 color developing agent ^* 4.189 kg hydroxylamine sulfate antioxidant 2.47 kg sodium sulfite 3.429 kg sodium bromide 175.397 g propylenediaminetetraacetic acid 2.414 kg ^* CD4 is 4- (N- Ethyl-N-β-hydroxyethylamino) -2-methylaniline sulfate. Part B : Potassium bicarbonate buffer Part C : Potassium carbonate buffer

Part A was mixed and aggregated using the same equipment and procedure as in Example 1, except that polyethylene glycol 900 was used as the hot melt binder, with similar excellent results.

Example 3 Preparation of an Ammonium Fixing Composition A black and white film fixing composition was prepared as a single-part composition using the following chemical components as follows: 4.617 kg of ammonium thiosulfate ethylenediaminetetraacetic acid Tetrasodium 49 g Sodium sulfite 930 g Citric acid 634 g Ammonium thiocyanate 5.684 kg Using the same procedure and procedure as in Example 1, this mixture was mixed and agglomerated with excellent results.

Example 4: Preparation of a sodium fixing composition A sodium-based fixing composition containing the following ingredients was prepared in the same manner: sodium thiosulfate 14.37 kg sodium tetraborate pentahydrate 151 g sodium pyrosulfite 1 .216 kg sodium citrate dihydrate 81 g ammonium alum sulfate decahydrate 2.437 kg boric anhydride (60 mesh) 202 g anhydrous citric acid 72 g sodium acetate anhydrous 1.467 kg Using the procedure and apparatus described in Example 1, This formulation was mixed and agglomerated with excellent results.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Franklin Charles Breyer New York, USA 14617, Rochester, Rock Beach Road 10

Claims (2)

[Claims] An agglomerate having a diameter of less than 20 μm is less than 0.2% by weight of the composition and the composition contains one or more solvents.
A process for the preparation of a homogeneous mixed photographic processing powder composition comprising less than 2% by weight of two or more photographic processing chemical components, comprising: A) two or more dry photographic processing chemical components To
The target uniformity (here, the target uniformity is defined as two or more random samples of the same size in a uniform dry mixture being ±± the target weight% of each component of the dry photographic processing chemical component).
4%) to form a homogeneous dry mixture thereof, and B) under conditions that form a target size agglomerate, the hot melt binder polymer ( However, the amount of the hot melt binder polymer in the obtained homogeneous mixed photographic processing powder composition is 3
(% By weight) and simultaneously aggregating the homogeneous dry mixture to form an agglomerate having a target size and a target uniformity in this order. Manufacturing method. 2. Two or more photographic processing chemical components wherein the agglomerates having an average diameter of less than 20 μm are less than 0.2% by weight of the composition and the composition comprises less than 1% by weight of solvent. A homogeneous mixed photographic processing powder composition comprising: A) two or more dry photographic processing chemical components,
The target uniformity (here, the target uniformity is defined as two or more random samples of the same size in a uniform dry mixture being ±± the target weight% of each component of the dry photographic processing chemical component).
4%) to form a homogenous dry mixture thereof, and B) under conditions that form a target size agglomerate, the hot melt binder polymer ( However, the amount of the hot melt binder polymer in the obtained homogeneous mixed photographic processing powder composition is 3
(% By weight), while simultaneously applying a uniform dry mixture to form an agglomerate having a target size and target uniformity, in this order. Photoprocessing powder composition.